Definition of "lock-in"

(US) A sleepover party, usually held in a public place such as a church or school, in which the participants are not allowed to leave until the next morning.  examples

(UK, Ireland) An illegal but widely-tolerated invitation-only gathering in a British pub, after the end of licensing hours, to allow regular customers the opportunity to enjoy further drinking time.  quotations  examples

(law) A situation in which members of an industry have agreed to adopt a certain standard and have retooled their production to meet this standard, thus making it very costly to change to a different standard.  examples

(finance) The situation where an investor cannot trade without incurring an undesirable penalty such as taxation.  examples